Table I.

Characteristics of the C₄ grass lineages

No., Lineage number; n, number of C₄ species. PCK, Phosphoenolpyruvate carboxykinase.

No.a	Name	Age Estimatesf	n	C3 Sister Group	C4 Subtype(s)	Cropsm	Habitatn
1b	Stipagrostis	15.1 (±4.6)–7.5 (±3.1)	50	Sartidiaa	NADP-ME	–	Deserts and semideserts
		NA
2b	Aristida	28.8 (±5.2)–14.4 (±4.7)	290	Sartidiaa	NADP-ME	–	Large ecological range
		[44.4 (±7.5)–present]
3b	Core Chloridoideae	32.0 (±4.4)–25.0 (±4.0)	1,410	Merxmuellera rangeiag	NAD-ME and PCK	Finger millet, teff	Large ecological range
		[37.6 (±6.6)–22.5 (±5.7)]
4b	Centropodia	22.0 (±4.6)–11.3 (±5.5)	4	M. rangeiag	NAD-ME	–	Dry open habitats (semideserts)
		NA
5c	Eriachne	11.5 (±3.6)–6.6 (±2.8)	40	Isachneagh	NADP-ME	–	Warm open habitats (savannah)
		NA
6b	Arundinelleae	26.4 (±4.4)–7.9 (±3.4)	95	Centotheceae 2agh	NADP-ME	–	Large ecological range
		[31.7 (±5.9)–present]
7cd	Panicum/Urochloa/Setaria clade	18.5 (±3.7)–16.4 (±3.6)	>530	C3Neurachnea	NADP-ME, NAD-ME, and PCK	Foxtail, pearl, and proso millets	Large ecological range
		[15.9 (±3.7)–13.1 (±3.2)]
8c	Neurachne munroi	4.4 (±3.3)–present	1	Neurachne tenuifoliaa	NADP-ME	–	Dry open habitats (steppes)
		NA
9c	Echinochloa	13.8 (±3.5)–4.4 (±2.8)	30–40	Parodiophyllochloaai	NADP-ME	–	Warm open habitats
		[20.6 (±4.5)–2.6 (±1.3)]
10b	Alloteropsis	15.3 (±3.5)–present	4–7	Forest shade cladeaj	NADP-ME and PCK	–	Warm open habitats (savannah)
		NA
11cd	Digitaria	21.2 (±3.9)–8.1 (±3.4)	220	x = 9 Paniceaea	NADP-ME	Fonio	Various warm open habitats
		[15.9 (±3.7)–5.4 (±2)]
12b	Andropogoneae	21.9 (±3.9)–17.1 (±4.1)	1,085	x = 10 Paniceaeak	NADP-ME	Maize, sorghum, sugarcane	Large ecological range
		[24.3 (±4.9)–19.1 (±4.5)]
13ab	Paspalum clade	14.1 (±3.4)–8.5 (±3.1)	>345	Streptostachys asperifoliaak	NADP-ME	Kodo millet	Warm open habitats (savannah)
		[11.7 (±3.1)–present]
13bc	Ophiochloa clade	10.6 (±3.3)–2.8 (±1.9)	115	S. asperifoliaa	NADP-ME	–	Large ecological range
		[13.7 (±3.5)–4.4 (±2.1)]
14b	Anthaenantiae	14.3 (±3.5)–present	1	Steinchisma cladeak	NADP-ME	–	Warm open habitats (savannah)
		[15 (±3.7)–present]
15c	Streptostachys ramosa	15.5 (±3.5)–present	1	Cyphonanthusl	NADP-ME	–	Warm open habitats (savannah)
		[16.3 (±3.7)–present]
16b	Panicum prionitis clade	10.4 (±2.9)–6.3 (±2.7)	>5	Arthropogon lanceolatusak	NADP-ME	–	Warm open habitats (savannah)
		[11.2 (±2.9)–present]
17c	Mesosetum clade	12.3 (±3.2)–11.3 (±3.0)	40	Homolepisak	NADP-ME		Warm open habitats (savannah)
		[14.8 (±3.5)–13.9 (±3.4)]

^aChristin et al. (2008).

^bIndependent origin confirmed by PEPC analyses (Christin et al., 2007).

^cIndependent origin based on putative species relationships only.

^dPhylogeny from Vicentini et al. (2008) found Digitaria and the main x = 9 Paniceae C₄ clade clustered together, suggesting a single C₄ origin.

^ePreviously named Leptocoryphium lanatum.

^fChristin et al. (2008) and Vicentini et al. (2008) into square brackets, ages are given in millions of years.

^gDuvall et al. (2007).

^hSánchez-Ken et al. (2007).

ⁱMorrone et al. (2008).

^jC₃ subspecies of A. semialata could represent a reversion from C₄ to C₃ (Ibrahim et al., 2009).

^kVicentini et al. (2008).

^lMorrone et al. (2007).

^mExcluding fodders.

ⁿWatson and Dallwitz (1992).